Fun to listen to...
The first silicone crack plugging is done. I will re-check it later, and probably caulk the screw holes (not used and they are tiny "ports" for my build, I guess.)
4-pole Neutrik Speakon on order from cloud so I can bridge the loathsome NU3000.
First listening impressions? The bass is definitely there, more "honest" for lack of a better term. I have stuff hooked up via a MiniDSP 2x4 and the "midranges" (4x Bose 901) are currently getting > 100 Hz. Of course, 4x 901s are capable of plenty of bass too. However, I don't know a way that I can easily A-B compare them. Yes I can load different profiles into the MiniDSP but switching might take too long. I do have REW, and may do some measurements later once I have the bugs (or, in my case, cats) out of the speaker -- literally.
Photos? Yeah, I should have taken some. But for now, the "sub" is on the long wall (about 14'), as unobtrusive as a cardboard tube can be. It sounds perhaps, like having a sub in two corners (not in phase, though).
The cats enjoy hiding in the tube. I can't wait to put on some loud music when he's in there but that may have to wait until ...
The girlfriend is visiting, awaiting her new home to move into. She is hobbyist tolerant, but not of loud music
The first silicone crack plugging is done. I will re-check it later, and probably caulk the screw holes (not used and they are tiny "ports" for my build, I guess.)
4-pole Neutrik Speakon on order from cloud so I can bridge the loathsome NU3000.
First listening impressions? The bass is definitely there, more "honest" for lack of a better term. I have stuff hooked up via a MiniDSP 2x4 and the "midranges" (4x Bose 901) are currently getting > 100 Hz. Of course, 4x 901s are capable of plenty of bass too. However, I don't know a way that I can easily A-B compare them. Yes I can load different profiles into the MiniDSP but switching might take too long. I do have REW, and may do some measurements later once I have the bugs (or, in my case, cats) out of the speaker -- literally.
Photos? Yeah, I should have taken some. But for now, the "sub" is on the long wall (about 14'), as unobtrusive as a cardboard tube can be.
It sounds perhaps, like having a sub in two corners (not in phase, though).The cats enjoy hiding in the tube. I can't wait to put on some loud music when he's in there but that may have to wait until ...
The girlfriend is visiting, awaiting her new home to move into. She is hobbyist tolerant, but not of loud music
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Hi Soldermizer
Quite a while back I wrote a simulator for the parallel transmission line system (B*se cannon). It does not have a gui and is just bare metal code. The assumption in the model is that the system folds and the exits are together. The speaker will be embedded in one side.
The bottom line is that I could never get a "good" alignment. The system makes a great one note wonder.
If you make it like the commercial implementation, most of the room will not have the outputs of the ends properly in phase.
Quite a while back I wrote a simulator for the parallel transmission line system (B*se cannon). It does not have a gui and is just bare metal code. The assumption in the model is that the system folds and the exits are together. The speaker will be embedded in one side.
The bottom line is that I could never get a "good" alignment. The system makes a great one note wonder.
If you make it like the commercial implementation, most of the room will not have the outputs of the ends properly in phase.
The ends of the pipe should be 1/2WL apart for smoothest response; eg: folded into a U or V shape, not straight. This way the 1/4W, 1/2W, 3/4W, and 1W resonances are equally excited for smoothest response and highest gain.
This is the embodiment of the Bose patent as seen in several GM cars, and is based on half-square antenna (RF) theory.
This is the embodiment of the Bose patent as seen in several GM cars, and is based on half-square antenna (RF) theory.
El-Pipe-O
One of the best documented sonotube sub-swoofers is Nelson Pass' El-Pipe-O. A friend built one, and it does move the earth if you use good drivers and enough amp power. I found on the internet a pdf copy of the 2002 article "The Legend of El Pipe-O" by Kent English and Nelson Pass, copyright 2002 Pass Labs. Unfortunately this system won't allow me to make attachments...
Do a google seach on "The Legend of El Pipe-O" and download the file. It has the detailed construction plans you need.
One of the best documented sonotube sub-swoofers is Nelson Pass' El-Pipe-O. A friend built one, and it does move the earth if you use good drivers and enough amp power. I found on the internet a pdf copy of the 2002 article "The Legend of El Pipe-O" by Kent English and Nelson Pass, copyright 2002 Pass Labs. Unfortunately this system won't allow me to make attachments...
Do a google seach on "The Legend of El Pipe-O" and download the file. It has the detailed construction plans you need.
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The simulator that I wrote is based on RF transmission line theory. It assumes that the exits are coincident. It could be changed to allow one exit to be delayed. Nevertheless, the ripple in band and unwanted output out of band was not what I want from a woofer system.
I did build a prototype to measure. It measures close enough to the simulator to let me know that the simulator is close enough for jazz. I also wrote a simulator for the parallel tuned bandpass (acoustimass) alignment and built one and measured it. That two models are very similar except for the recurring Smith Chart behavior of the parallel transmission line (cannon).
The cat's in the subwoofer with a silver spoon...
OK actually this is just a follow up. The beast (the sub) is still working. It will hit 15 Hz. I am itching to tweak it some. I'll admit I have yet to use a calculator but I did discover this: I think I lucked out with my choice of sub, it is a high Qts (=0.52) which is recommended (stiffness?) for a TL. I know the Fs = 27 Hz (+/- 15%) and here is the question: shall I trim the sonotube for fine tuning? Length or stuffing the tube is the only easy mod option for now. I did these calculations based just on wavelength:
freq (HZ) wavelength (feet)
23 12.24
27 10.43
31 9.08
The "for dummies" pdf referenced in this thread says best to start tuned too low for a high-Q woofer. That would be my case. I am not sure what I can test for, or even how, and the question might be: is it worth adjusting the tuning to "spec"? I do have a jigsaw
For the record, I posit that 23.6 Hz would be the ideal Fs for a driver for a 12 foot sonotube.
Would the change in performance even be noticeable?
OK actually this is just a follow up. The beast (the sub) is still working. It will hit 15 Hz. I am itching to tweak it some. I'll admit I have yet to use a calculator but I did discover this: I think I lucked out with my choice of sub, it is a high Qts (=0.52) which is recommended (stiffness?) for a TL. I know the Fs = 27 Hz (+/- 15%) and here is the question: shall I trim the sonotube for fine tuning? Length or stuffing the tube is the only easy mod option for now. I did these calculations based just on wavelength:
freq (HZ) wavelength (feet)
23 12.24
27 10.43
31 9.08
The "for dummies" pdf referenced in this thread says best to start tuned too low for a high-Q woofer. That would be my case. I am not sure what I can test for, or even how, and the question might be: is it worth adjusting the tuning to "spec"? I do have a jigsaw
For the record, I posit that 23.6 Hz would be the ideal Fs for a driver for a 12 foot sonotube.
Would the change in performance even be noticeable?
Hey, Sod, those tubes come in three sized per size find one that slips over it and voila! You can tuna fish.
OK actually this is just a follow up. The beast (the sub) is still working. It will hit 15 Hz. I am itching to tweak it some. I'll admit I have yet to use a calculator but I did discover this: I think I lucked out with my choice of sub, it is a high Qts (=0.52) which is recommended (stiffness?) for a TL. I know the Fs = 27 Hz (+/- 15%) and here is the question: shall I trim the sonotube for fine tuning? Length or stuffing the tube is the only easy mod option for now. I did these calculations based just on wavelength:
freq (HZ) wavelength (feet)
23 12.24
27 10.43
31 9.08
The "for dummies" pdf referenced in this thread says best to start tuned too low for a high-Q woofer. That would be my case. I am not sure what I can test for, or even how, and the question might be: is it worth adjusting the tuning to "spec"? I do have a jigsaw
For the record, I posit that 23.6 Hz would be the ideal Fs for a driver for a 12 foot sonotube.
Would the change in performance even be noticeable?
At first I thought you were being an "intelligent donkey" but I during my researching this cockamammie project, I recall a message that said, yes, Sonotube comes in slightly varying sizes per "diameter" (why?) Odd! You have a good point, but must my subwoofer become an immense version of a slide whistle 
?
Depending upon the other responses, I will either (1) leave well enough alone or (2) cut to the "calculated" length. I wish I had measured the true Fs of my driver before it was installated in the tube. Of course that would require that I knew how to measure it? Or it is done by inspection?
I still like the angle that this may be the one speaker (sub) that can be built that is potentially 100% free of any carpentry. Huge tube, driver, glue or other way to affix to one end, solder your wires and thump and drone away. I mean really, I know this is a DIY forum but it's like I am being evangelized by every woodworker trying to convince me that I could build any kind of box at all.
"There was one room in my house that was always kept locked. That room was -- the garage!" -- Thomas Dolby
but I during my researching this cockamammie project, I recall a message that said, yes, Sonotube comes in slightly varying sizes per "diameter" (why?) Odd! You have a good point, but must my subwoofer become an immense version of a slide whistle ?Depending upon the other responses, I will either (1) leave well enough alone or (2) cut to the "calculated" length. I wish I had measured the true Fs of my driver before it was installated in the tube. Of course that would require that I knew how to measure it? Or it is done by inspection?
I still like the angle that this may be the one speaker (sub) that can be built that is potentially 100% free of any carpentry. Huge tube, driver, glue or other way to affix to one end, solder your wires and thump and drone away. I mean really, I know this is a DIY forum but it's like I am being evangelized by every woodworker trying to convince me that I could build any kind of box at all.
"There was one room in my house that was always kept locked. That room was -- the garage!" -- Thomas Dolby
In all modesty I think that would be me, I looked around everywhere and could not find anything exactly like it, but I see it as a no brainer. However one thing I've learned here is that speaker people will take extraordinary credit for inventing the obvious!!! I do like your name with one addition, because I want credit for inventing something obvious too.
"The Leoni Trobone TL"
(-,
Just thinking. With those 5 foot sections they sell at Lowes you could buy 1 to mount speaker in end and two more to nest/override the main chamber, rear should be one fith to.one third the front chamber. They are inexpensive, then you could tune rear and front chambers, can't see how you can miss if I am interpreting Martin Kings stuff correctly. Then after tuning gorilla tape. Or truck bed liner would further stiffen and complete.
Or, to continue the tradition Pass did (name your sub after a "smoking device") we could call it the "Musket." Around 1979, this was a little disposable pipe made of cardboard that you loaded with your favorite, er, smoking material. It had a metal disc on the end and was basically two tubes, one inside the other. It was a single-use pipe and "smokeless" (I guess they never consider one needs to exhale!).
As far as easily adjustable, foul play! In the true spirit of DIY, if a fly so much as defecates on the surface of a woofer, that will by definition change the Fs and requires a complete re-design, re-calculation, tear-down and reassembly of all components. Or in my case, how do I adjust my stuffing equation to include the cat(s) in the Sonotube ?
As far as easily adjustable, foul play! In the true spirit of DIY, if a fly so much as defecates on the surface of a woofer, that will by definition change the Fs and requires a complete re-design, re-calculation, tear-down and reassembly of all components. Or in my case, how do I adjust my stuffing equation to include the cat(s) in the Sonotube ?
The length and diameter of the tube(s) determine the tuning regardless of the Fs. As long as it is a fly (not an elephant) defecating on your woofer, not to worry.
A cat in the tube reduces the volume of the tube, and provides some damping.
There are a wide variety of cats, you will need to provide specifications of yours and where it lies in the tube for a valid simulation to be created
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